MEXICO CITY - Authorities said Tuesday they will fire nine investigators and suspend 21 others for misconduct related to the 2014 army slayings of 22 suspected gang members in central Mexico.

More than 50 officials from the central State of Mexico were under investigation for alleged abuses committed during the coverup of the bloodshed at a grain warehouse. The country's human rights commission has said soldiers killed at least a dozen of the suspects after they surrendered.

Israel Montoya, head of the internal affairs division at the Mexico State prosecutor's office, said the 52 employees investigated included detectives, supervisors and crime scene experts. Montoya said 30 got some form of punishment.

Two of the three survivors of the slayings told The Associated Press that state detectives and prosecutors' agents tortured and threatened them to go along with the army's version that all the suspects had died during a shootout with troops.

Montoya said all the disciplinary actions were for failure to correctly perform their duties.

A year ago, Mexico State prosecutors formally accused seven state police officers of torturing all three women who survived the confrontation. Trials in Mexico frequently last for years and there was no immediate information on whether any of the officers have been convicted.

On July 1, 2014, a day after the shooting, Mexico State Gov. Eruviel Avila publicly thanked the army for its "bravery" and "firmness" in the confrontation. Manzur said later that the governor's statement was meant to thank the army "for freeing three kidnap victims, not for the violent actions."

Originally considered kidnap victims, two of the three survivors were jailed for months on weapons charges before being released. They claim they were tortured while in custody.

The federal government's human rights commission found that between 12 and 15 of the suspects cornered at a warehouse on June 30, 2014, surrendered but were shot anyway. It also said there was evidence the scene had been altered.

The army initially said all 22 dead were killed in a fierce gunbattle with soldiers after a patrol came under fire at the warehouse in the town of San Pedro Limon. It said only one soldier was wounded.

Seven low-ranking soldiers, including a lieutenant, were charged in the case but were later acquitted or the charges were dropped.